200817777 九、發明說明 【發明所屬之技術領域】 本發明，係有關例如液晶顯示裝置之背光單元般地， 從發光面射出均一亮度分布之照明光線的中空式面照明裝 置。 【先前技術】 近年來，做爲液晶顯示裝置之背光單元用的光源，係 從冷陰極放電燈進步到由LED代替。這是因爲LED不含 有害物質之水銀，適合做爲環保型光源，還有最近大幅提 高發光效率而可大幅降低消耗電力之故。具備LED做爲 光源之背光單元，目前以對應行動電話或行動終端機等小 型機器的用途爲中心，但是最進也進步到被20吋以上之 液晶螢幕或液晶電視等大型液晶顯示裝置所採用。 大型液晶顯示裝置之情況下，該背光單元會被要求高 亮度。因此小型背光單元一般所採用，在導光板側部配置 光源使其發光，從導光板側面來導光而擴散、反射，來從 導光板外面側之面發光部射出的邊緣發光方式，並不能被 採用爲大型液晶顯示裝置的背光。做爲大型液晶顯示裝置 用之背光單元，係如日本特開2005 - 3 1 63 3 7號公報所記載 ，一般是在面發光部正下方配置LED光源的直下型背光 單元。 此種直下型背光單元，因爲光源是LED，故排列後之 多數LED與面發光部的距離若太接近，則會被辨識爲亮 200817777 度不均、色彩不均，使得其照明之液晶的顯示品質惡化。 此現象，在爲了實現高亮度，而將每1個之電力爲1W等 級以上的高輸出LED做爲光源時，尤其明顯。反過來看 ，爲了降低亮度不均、色彩不均，而拉遠LED與面發光 部（擴散板）的距離，會導致裝置整體厚度增加，有違近 年來薄型化之傾向而不理想。 做爲可薄型且大型化之中空式邊緣發光方式的背光單 元，已知有日本特開平8 - 1 7 1 8 0 6號公報所記載者。此文 件所記載之背光單元，係於機殼具備有：在一側邊具備有 射光部之長條狀光源；和在此光源之光射出方向前方側底 部擴張，將自該光源遠離之部位向上傾斜的亂反射層；和 將此亂反射層所亂反射之光線向上面導引的空氣層；和設 置於機殻上面的光擴散層；和靠近配置於光源之射光部的 長條狀凸透鏡體。此先前之背光單元，係藉由長條狀凸透 鏡體之聚光特性，使來自長條狀光源之光線會聚光在亂反 射層的1個場所；其要對發光面整體得到均一亮度，尤其 就大面積之背光單元來說是困難的問題點。 另一方面，做爲中空式邊緣發光式背光單元，已知有 日本特開2006- 1 062 1 2號公報（專利文件3 )所記載者。 然而此文件3所記載之背光單元，其光源之LED數量較 少，有難以將做爲背光單元所需之白色光做大面積發光的 問題點。 【發明內容】 -5- 200817777 發明所欲解決之課題 本案中所謂「邊緣發光方式」，係從發光面之背部側 邊的光源，射出對發光面平行之方向的光線，將此光線折 射、反射、擴散而導光至發光面的照明方式。 本發明係有鑑於上述之先前的技術課題而完成者，其 目的爲提供一種邊緣發光方式之中空式面照明裝置，其不 必將裝置大型化，就可達成照明光的高亮度化以及照度的 高度均一化。 用以解決課題之手段 本發明之特徵點，係在於一種中空式面照明裝置，在 中空之單元箱的底面側配置光反射面構件；在上述單元箱 之與上述光反射面構件相向的外面側，配置發光面構件； 將上述單元箱中，由上述光反射面構件與發光面構件所夾 的空間，做爲中空導光區域；使於配線基板1表面黏著成 列設置多數個LED而成的LED光源鄰接於上述中空導光 區域，以可射出至該中空導光區域的方式來配置；將相對 於單元厚度方向之LED光軸上以成爲平行之方式把來自 上述LED光源的光線予以聚光之LED準直器，以與上述 LED之排列呈平行地配置在上述LED光源的射出部；於 上述LED準直器，係設置有：讓來自上述LED排列之光 線折射，導入箱體內或射出的折射聚光功能部，以及讓導 入體內之光線全反射而射出到上述中空導光區域的全反射 聚光功能部。 -6- 200817777 上述中空式面照明裝置中，上述單元箱之光反射面構 件，可以使用具有高反射率之擴散反射性構件。 又，上述中空式面照明裝置中，上述單元箱之發光面 構件，可使用能讓來自上述中空導光區域之光線透過並擴 散的光透過性擴散構件。 更且，上述中空式面照明裝置中，上述LED光源， 係將紅色LED與藍色LED以特定排列方式表面黏著成列 設置於上述配線基板；並且，在上述中空導光區域之外面 側，且爲上述發光面構件之內面側，可設置吸收上述藍色 LED所放出之藍色光線而轉換爲綠色光線的波長轉換薄片 〇 若依本發明，藉由在LED光源之射出側配置LED準 直器，可以將LED光源之光線變成有效率且平行度較高 的光線，導入單元箱內之中空導光區域，而可從面發光部 均一地射出；結果，可射出高亮度且均一度也高的光線， 而可提供一種能被採用爲大型液晶顯示裝置之背光單元的 LED光源、邊緣發光方式的中空式面照明裝置。 【實施方式】 以下，依據圖示詳細說明本發明之實施方式。 (第1實施方式）第1圖、第2圖係表示本發明之一 種實施方式中，做爲中空式面照明裝置的液晶顯示裝置用 背光單元。此背光單元係在矩形之單元箱1的底面中央， 配置有沿著平行於一個邊之線隆起爲山型’其稜線兩側越 200817777 途則越來越低之山型的光反射構件2。在此單元箱1之表 面開口面’配置有發光面構件3。然後在單元箱1從發光 面構件3側覆蓋前框體4，與單元箱1 一體化，藉此完成 本實施方式的背光單元。單元箱！內，由光反射面構件2 與發光面構件3所包夾的空間部份，則成爲中空導光區域 10。 光反射面構件2，係於金屬或樹脂等基材層積上高反 射性’且具有擴散反射性的材料，例如白色P E T薄膜或白 色墨水，且製爲與發光面3之距離會改變的形狀，以使發 光面構件3中之亮度分布可成爲均一化。做爲具有光擴散 反射性之材料，除了上述以外，也可以在具有鏡面反射性 之高反射鋁等塗佈光透過性擴散材料。 發光面構件3，係最少對光透過擴散板3 a，更加重疊 上擴散薄片3B、3C，透鏡薄片3D等光學薄片而成者；將 通過中空導光區域1 0 ’碰到山型之光反射構件2而反射過 來的光線加以均一地擴散、射出，藉此達成使發光面亮度 沒有不均，均一度提高的工作。 單元箱1，係由鋁合金等高熱傳導性的金屬所形成。 此單元箱1中平行於光反射面構件2之稜線的兩側面，分 別配置有LED基板5。此LED基板5，係在具有單元箱1 之該側面可收容之寬度的細長配線基板6上，將多數個 LED 71表面黏著成列設置爲一列或複數列者。配線基板6 係由高熱傳導性之鋁系、銅系合金等金屬，或氮化鋁等陶 瓷所形成，以螺絲、黏者或其他手段固定在局熱傳導性之 -8- 200817777 單元箱1的側壁。另外，此配線基板6與單元箱1之側壁 之間，介入有高熱傳導性之雙面膠帶、薄片或油膏等爲佳 。安裝於LED基板5上之LED7，係使用以爲了合成期望 之白色色度的數量比，而配置的紅色、綠色、藍色等3色 LED ;或是藉由藍色LED晶片與黃色螢光體之組合，來發 出白光的複數LED。 然後LED基板5之射出側與中空導光區域1 0之間， 配置有細長的LED準直器9，其覆蓋LED7之排列，並形 成有由將LED7所擴散放射之放射光加以入光之凹溝8所 構成的入射面。 此LED準直器9，係由將安裝於LED基板5之LED 7 所擴散放射之放射光加以入光的凹溝8，和連接該凹溝8 之上下兩端而彎曲的全反射面，和聯繫結合複數彎曲面的 放射面所形成；是一種用以將在此放射面以高度爲準而聚 光爲略平行光的光線，入光到中空導光區域1 0的光學構 件；例如由丙烯酸或聚碳酸酯等透明樹脂，或是玻璃來形 成。 如第3圖、第4圖詳細表示般，LED準直器9中面對 LED 7列的入射部側形成有凹溝8。此凹溝8之溝壁面， 係成爲將接近LED7光軸之角度之放射光導光到體內的凸 形狀入射面InA ;和將遠離LED7光軸之角度之放射光導 光到體內的平面形狀入射面ΙηΒΙ、ΙπΒ2。LED準直器9 在圖中位於下側與上側的側面，係彎曲爲能夠全反射體內 之光線的全反射面TIR1、TIR2。LED準直器9之出射部 200817777 ，係成爲對應來自入射面InA之入射光的凸形狀出射面 ExA ;和對應自入射面ΙηΒΙ、ΙπΒ2射入後，被全反射面 ΤIR 1、ΤIR 2全反射之光線的凹曲面形狀出射面Ε X Β 1、 ΕχΒ2。 上述實施方式之背光單元，係如第4圖詳細表示般， 藉由LED準直器9，可將來自LED基板5中LED7之光線 聚光到中空導光區域1 〇的厚度方向，而射入到此中空導 光區域1 0。亦即在LED準直器9中，從LED7射入到入 射面InA之光RYA，係在剖面凸形狀之入射面InA及出射 面ExA折射，而被聚光在中空導光區域1〇的厚度方向。 又，射入到入射面ΙηΒ1、ΙηΒ2之光線RYB1、RYB2，會 藉由全反射面TIR1、TIR2之全反射與出射面ExBl、ExB2 的折射，而被聚光在中空導光區域10的厚度方向。 從LED準直器9射出到中空導光區域1〇之光線RYA 、RYB1、RYB2，係在形狀被最佳化之反射面構件2的反 射面，被反射到發光面構件3的方向，而從此發光面構件 3之發光面，以高亮度且沒有亮度不均的狀態射出。 若依本實施方式之背光單元，藉由LED準直器9之 存在，可將自光源亦即LED7以廣角度所放射之光線，用 光利用效率8 0 %以上之高效率且窄角度來聚光，將中空導 光區域1 〇中之反射損失控制到最低限度，而比起先前之 中空方式之背光單元可更加提高亮度。又，先前之中空方 式之背光單元，爲了使光線能從光源盡量到達遠方，係將 中空導光區域之反射面做爲鏡面反射性，或是接近鏡面的 -10- 200817777 反射特性，而在發光面會產生局部性亮線；但是本實施方 式之背光單元之情況下，因爲光源之聚光性較高，故即使 將反射面做爲擴散反射性也可提高亮度均一度，且可防止 局部性売線的產生。 第5圖，係針對本實施方式之背光單元3 0，對分別設 置於發光面之相向兩側面的一對LED光源5，將其造成之 光源線的直角方向（正交於LED排列方向或是平行於 LED光軸方向的方向）做爲亮度分布測定線3 1，表示在 該亮度分布測定線3 1上一對LED光源5所造成之光源線 之間的亮度分布。另外，LED光源5在此情況下，於第5 (a )圖之背光單元3 0中，係被設置爲相向於上下個別的 長邊。 (第2實施方式）使用第6圖、第7圖，說明本發明 第2實施方式之背光單元。本實施方式之背光單元，特徵 係做爲LED準直器9A，是使用第6圖、第7圖所示者； 雖然與第1圖、第2圖所示之第1實施方式的LED準直 器9爲相同形狀，但是將凹溝8A之溝壁面所構成的入射 面InA、InBl、InB2做爲稜鏡面。另外本實施方式中，其 他構造與第1圖、第2圖所示之第1實施方式的背光單元 共通。 本實施方式之背光單元，係如第7圖所示，來自LED 基板5上之LED7的光線，在從凹溝8A之溝壁面所構成 的入射面InA、InBl、InB2射入LED準直器9時，會於 稜鏡面有效率地往LED準直器方向擴散。從而來自LED7 -11 - 200817777 之光線，擴散到此LED準直器9的整個體內之後，從出 射面ExA、ExBl、ExB2射出到中空導光區域10。然後與 第1實施方式一樣，從LED準直器9A射出到中空導光區 域1 〇的光線，在形狀被最佳化之反射面構件2的反射面 ，被反射到發光面構件3的方向，而從此發光面構件3之 發光面，以高亮度且沒有亮度不均的狀態射出。 另外本實施方式中，LED準直器9A之由凹溝8A之 溝壁面所構成的入射面ΙηΑ、ΙηΒΙ、ΙιιΒ2係全部做爲棱鏡 面，但是僅將其中一面或兩面做爲稜鏡面，也可提高光擴 散效果。 (第3實施方式）使用第8圖、第9圖，說明本發明 第3實施方式之背光單元。本實施方式之背光單元，特徵 係做爲LED準直器9B，是使用第8圖、第9圖所示者； 雖然與第1圖、第2圖所示之第1實施方式的LED準直 器9爲相同形狀，但是將長邊方向之兩端部分別以凹溝 8B來中斷，將該凹溝8B之溝端壁面做爲端部入射面inC ;又，將LED準直器9B之端面做爲端部全反射面TiR3。 另外本實施方式中，其他構造也與第1圖、第2圖所示之 第1實施方式的背光單元共通。 本實施方式之背光單元，係如第9圖所示，來自LED 基板5上之LED7的光線，係從凹溝8B之溝壁面所構成 的入射面ΙηΑ、ΙηΒΙ、InB2射入LED準直器9，同時在長 邊方向之兩端部也從端部入射面InC射入。然後在LED 準直器9B內部，與第4圖所示相同，將入射光折射或全 -12- 200817777 反射，從出射面ExA、ExB 1、ΕχΒ2有效聚光而射出到中 空導光區域10;同時在LED準直器9Β之兩端部，則如第 9圖所示，將從端部入射面InC射入到端部體內之光線， 以端部全反射面TIR3做全反射，從出射面ExA、ExB 1、 ExB2射出到中空導光區域10。 藉此，本實施方式之背光單元中，來自位於LED基 板5之端部之LED7的光線，可抑制其在接觸單元箱1之 壁面時的反射及吸收耗損，而可提高發光面的亮度。 另外，此第3實施方式中，也可與第2實施方式一樣 ，將凹溝8B之溝壁面一面或複數面做爲稜鏡面，藉此可 提升對LED準直器8B入射光的擴散情況。 (第4實施方式）使用第10圖〜第12圖，說明本發 明第4實施方式之背光單元。本實施方式之背光單元，特 徵係LED基板5之構造，和配置在中空導光區域2之外 面側，並且爲發光面構件3之內面側的波長轉換薄片1 3 0 。另外本實施方式中，其他構造也與第1圖、第2圖所示 之第1實施方式的背光單元共通。 如第10圖、第11圖所示，本實施方式之背光單元中 ，LED基板5係在配線基板6上交互排列有發出藍色光線 的藍色LED7B與發出紅色光線的紅色LED7R，來排列構 成；不像其他實施方式有使用率色LED。又，爲了將藍色 光與紅色光與綠色光混合做爲白色光，係在中空導光區域 1 〇之初光面側亦即外面側，且爲發光面構件3的內面側， 設置將藍色光轉換爲綠色光的波長轉換薄片1 3 0。 -13- 200817777 藍色LED7B與紅色LED7R，係準備爲例如個別之數 量爲2 : 1的比例，或亮度爲2 : 1的比例，來安裝於配線 基板6。此等LED可以是表面發光型，也可以是端面發光 型。但是都被鑲嵌爲該發光可射入到準直器9的凹溝8內 〇 紅色LED7R之放射光的峰値波長以5 90〜670nm的範 圍爲佳。此種發光元件，可使用例如InGaA1P系的化合物 半導體來實現。對應各種用途，調整紅色 LED7R之 InGaAlP活性層的成分等，可藉此得到此波長範圍中最理 想的峰値波長。另一方面，藍色LED 7B之放射光的峰値 波長以420〜48 Onm的範圍爲佳。此種發光元件，可使用例 如InGaAIN系的化合物半導體來實現。對應各種用途，調 整藍色LED7B之InGaAIN活性層的成分等，可藉此得到 此波長範圍中最理想的峰値波長。 波長轉換薄片1 3 0係由樹脂所形成。亦即波長轉換薄 片130，係在樹脂中分散螢光體而成型爲薄片狀者。此波 長轉換薄片1 3 0係在透光性薄膜表面（或背面）塗佈螢光 體者。 分散或包含於波長轉換薄片1 3 0之螢光體，係吸收從 藍色LED 7B放射之藍色光，而放射綠色光者。綠色光之 峰値波長以520〜560nm的範圍爲佳。做爲此種螢光材料， 可舉出例如於ZnS添加Cu或A1者，或是於（Ba · Mg ) Α1ι〇017添加Eu或Μη者。 第12Α圖〜第12D圖，係例舉波長轉換薄片130的剖 -14- 200817777 面構造。亦即第12A圖，係表示在樹脂等薄膜狀之母體 13 0c表面，塗佈螢光層130f而形成的波長轉換薄片130 。又，第12B圖表示在樹脂母體中分散螢光體而形成的波 長轉換薄片130。第12C圖，表示層積複數透光性薄膜 13 0c，在其間設置塗佈或分散有螢光體之層130s，而爲此 種構造的波長轉換薄片1 3 0。更且，波長轉換薄片1 3 0不 需要是一體構造，也可如第1 2D圖所示，分別將含有螢光 體之複數薄膜130s加以層積構成。又，波長轉換薄片130 可以與發光面構件3分開，也可以一體形成。 若依本實施方式，藉由調節波長轉換薄片1 3 0所包含 之螢光體的材質或成分，就可調節綠色光的波長。例如當 作LCD之背光來使用時，藉由適當選擇波長轉換薄片130 所包含之螢光體的材質或成分，可以得到符合LCD之綠 色彩色濾光片之透過特性的光線。如此一來，就不需要使 用效率較低的綠色LED。結果，可降低整體成本並得到較 高亮度與顏色重現性。 又，若依本實施方式，則綠色發光不是在LED基板5 側，而是在發光面側由波長轉換薄片1 3 0來得到。從而， 可以消除使用綠色LED時所產生之綠色LED個別差異所 造成的特性不一致。又，波長轉換薄片1 3 0，係被由光反 射面構件2提高均一度的藍色發光所激發，故不需要爲了 使發光面構件3之出光面整體的綠色亮度分布均一，而針 對波長轉換薄片1 3 0之各部份調整波長轉換用的螢光體濃 度分布。亦即以綠色波長轉換光之亮度爲藍色激發光之亮 -15- 200817777 度之5倍以上的方式，將波長轉換用螢光體之濃度調整爲 於整個波長轉換薄片1 3 〇都一樣即可。如此一來，最後從 發光面構件3所放射的光線，可得到對應人類視覺感受的 白色光。 又，若依本實施方式，則藉由獨立控制施加於紅色 LED 7R的電流値，也可將紅色光之亮度控制在綠色光的 1 /5左右。同樣的，藍色光與紅色光的亮度比也可控制， 故色溫也可在一定範圍內作調整。此時，比起將RGB三 色LED分別以所謂RGB排列方式來調整3色LED，其控 制電路會更簡單。 將紅色LED、藍色LED和吸收藍色光而發出綠色光 的螢光體，密封在相同封裝內，成爲放出白色光之白色 LED封裝的情況下，一旦混入螢光體則綠亮度/藍亮度比 會固定，之後就無法調節。以特定分布、濃度將螢光體對 每個封裝安定混入，實際上是很困難的。亦即綠亮度/藍 亮度的比値常常於每個封裝都有不同。因此製造完成後， 使用沒有加上後期工程之封裝製品，則難以控制爲特定亮 度比（5 : 1 )，會延滯成品率而需要挑選。 相對地，若依本實施方式，則藍色L E D 7 B與含有螢 光體之長轉換薄片1 3 0是分別來構成。從而，藉由適當組 合此等，可輕易調整藍色光與綠色光的亮度平衡。例如， 預先準備綠色螢光體含量不同的複數波長轉換薄片130， 配合從面發光構件3之外面側所發出的藍色光亮度，選用 此等複數波長轉換薄片1 3 0中的任一種，將藍色光與綠色 16- 200817777 光的平衡調整到最佳。 又’例如做爲波長轉換薄片1 03，如第1 2D圖所示， 採用層積含有螢光體之複數薄膜的層積構造時，也能得到 可輕易變更螢光體含量的效果。亦即配合從藍色螢光體 LED 7B放出的藍色光亮度，和因應用途所分別要求之綠色 /藍色的平衡，來層積必要片數的薄片，藉此可得到最佳 的平衡。 【圖式簡單說明】 第1圖，係本發明之第1實施方式之背光單元的分解 立體圖。 第2圖，係上述第1實施方式之背光單元的剖面圖。 第3圖，係上述第1實施方式所採用之LED準直器 的部份切開立體圖。 第4圖，係表示上述第1實施方式中LED準直器之 聚光特性的剖面圖。 第5圖，係表示上述第1實施方式之背光單元之亮度 分布特性的圖表。 第6圖，係本發明第2實施方式之背光單元所採用之 LED準直器的部份切開立體圖。 第7圖，係表示上述第2實施方式中LED準直器之 光擴散特性的剖面圖。 第8圖，係本發明第3實施方式之背光單元所採用之 LED準直器的部份切開立體圖。 -17- 200817777 第9圖，係表示上述第3實施方式中，在LED細面 之光線動作的剖面圖。 第10圖，係本發明第4實施方式之背光單元的分解 立體圖。 第1 1圖，係上述第4實施方式之背光單元的剖面圖 〇 第12A圖，係表示上述第4實施方式中波長轉換薄片 之構造例的剖面圖。 第12B圖，係表示上述第4實施方式中波長轉換薄片 之其他構造例的剖面圖。 第12C圖’係表示上述第4實施方式中波長轉換薄片 之更其他構造例的剖面圖。 弟12D圖’係表不上述第4實施方式中波長轉換薄片 之更其他構造例的剖面圖。 【主要元件符號說明】 1 :單元箱 2 :光反射面構件 3 :發光面構件 3 A :光透過擴散板 3B :擴散薄片 3C :擴散薄片 3 D :透鏡薄片 4 :前框體 -18- 200817777 5 : LED基板 6 :配線基板BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow surface illumination device that emits illumination light of a uniform luminance distribution from a light-emitting surface, for example, in a backlight unit of a liquid crystal display device. [Prior Art] In recent years, a light source for a backlight unit of a liquid crystal display device has progressed from a cold cathode discharge lamp to an LED replacement. This is because the LED does not contain mercury, which is a harmful substance, and is suitable as an environmentally-friendly light source. Recently, it has greatly improved luminous efficiency and can greatly reduce power consumption. A backlight unit that uses LED as a light source is currently used for small-sized devices such as mobile phones and mobile terminals, but it has also been advanced to large liquid crystal display devices such as liquid crystal screens or liquid crystal televisions that are 20 inches or more. In the case of a large liquid crystal display device, the backlight unit is required to have high brightness. Therefore, a small-sized backlight unit is generally used, and a light source is disposed on the side of the light guide plate to emit light, and light is diffused and reflected from the side surface of the light guide plate to emit light from the surface light-emitting portion on the outer surface side of the light guide plate. A backlight is used for a large liquid crystal display device. As a backlight unit for a large-sized liquid crystal display device, a direct type backlight unit in which an LED light source is disposed directly under the surface light-emitting portion is generally described in Japanese Laid-Open Patent Publication No. Hei. In such a direct type backlight unit, since the light source is an LED, if the distance between the majority of the LEDs and the surface light emitting portion is too close, it will be recognized as bright 200817777 degree unevenness and uneven color, so that the liquid crystal display thereof is illuminated. The quality deteriorated. This phenomenon is particularly noticeable when a high-output LED having a power of 1 W or more per one power source is used as a light source in order to achieve high luminance. Conversely, in order to reduce uneven brightness and uneven color, the distance between the LED and the surface emitting portion (diffusion plate) may increase, and the overall thickness of the device may increase, which is contrary to the tendency of thinning in recent years. As a backlight unit which is a thin-type and large-sized hollow edge light-emitting type, it is known as described in Japanese Laid-Open Patent Publication No. Hei 8-7-1866. The backlight unit described in this document is provided with a long-length light source having a light-emitting portion on one side, and a bottom portion extending in front of the light-emitting direction of the light source, and the portion away from the light source is upward. a slanted reflective layer; an air layer that directs the light reflected by the swash layer to the upper surface; and a light diffusion layer disposed on the upper surface of the casing; and an elongated convex lens body disposed adjacent to the light emitting portion of the light source . In the prior backlight unit, the light from the long light source is concentrated in one place of the random reflection layer by the condensing property of the elongated convex lens body; the uniform brightness of the entire light emitting surface is obtained, especially A large area of backlight unit is a difficult problem. On the other hand, as a hollow edge type light-emitting type backlight unit, those described in Japanese Laid-Open Patent Publication No. 2006- 1 062 1 2 (Patent Document 3) are known. However, in the backlight unit described in the document 3, the number of LEDs of the light source is small, and it is difficult to make the white light required for the backlight unit to emit light in a large area. SUMMARY OF THE INVENTION - 5 - 200817777 Problem to be Solved by the Invention In the present invention, the "edge light-emitting method" is a light source that is parallel to the light-emitting surface from a light source on the back side of the light-emitting surface, and refracts and reflects the light. The method of illumination that diffuses and directs light to the light-emitting surface. The present invention has been made in view of the above-described problems of the prior art, and an object of the invention is to provide a hollow-surface illumination device of an edge-emitting type, which can achieve high brightness of illumination light and height of illumination without increasing the size of the device. Uniformity. Means for Solving the Problem A feature of the present invention is a hollow-surface illumination device in which a light-reflecting surface member is disposed on a bottom surface side of a hollow unit case, and an outer surface side of the unit case facing the light-reflecting surface member a light-emitting surface member is disposed; wherein a space between the light-reflecting surface member and the light-emitting surface member in the unit case is a hollow light guiding region; and a plurality of LEDs are arranged in a line on the surface of the wiring substrate 1 The LED light source is disposed adjacent to the hollow light guiding region so as to be emitted to the hollow light guiding region; the light from the LED light source is condensed in parallel with respect to the optical axis of the LED in the thickness direction of the unit The LED collimator is disposed in parallel with the arrangement of the LEDs on the emitting portion of the LED light source; and the LED collimator is provided to refract light from the LED array and introduce it into the housing or to emit the light. The refracting concentrating function portion and the total reflection condensing function portion that totally reflects the light introduced into the body and emits the light into the hollow light guiding region. -6- 200817777 In the above hollow type illuminating device, a diffuse reflective member having a high reflectance can be used as the light reflecting surface member of the unit case. Further, in the above-described hollow type illuminating device, a light-transmitting diffusion member capable of transmitting and diffusing light from the hollow light guiding region can be used as the light-emitting surface member of the unit case. Further, in the above-described hollow type illuminating device, the LED light source is provided with a red LED and a blue LED adhered to each other in a specific arrangement on the surface of the wiring substrate, and on the outer surface side of the hollow light guiding region, and A wavelength conversion sheet that absorbs the blue light emitted by the blue LED and converts it into green light can be disposed on the inner surface side of the light-emitting surface member. According to the present invention, LED alignment is disposed on the emission side of the LED light source. The light source of the LED light source can be converted into light with high efficiency and high parallelism, and is introduced into the hollow light guiding region in the unit box, and can be uniformly emitted from the surface light emitting portion; as a result, high brightness and uniformity can be emitted. The light can provide an LED light source that can be used as a backlight unit of a large liquid crystal display device, and a hollow surface illumination device that is edge-lit. [Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) Fig. 1 and Fig. 2 show a backlight unit for a liquid crystal display device which is a hollow type illuminating device according to an embodiment of the present invention. This backlight unit is disposed at the center of the bottom surface of the rectangular unit case 1, and is provided with a mountain-shaped light-reflecting member 2 which is ridged along a line parallel to one side and has a hill shape on both sides of the ridge line. The light-emitting surface member 3 is disposed on the surface opening surface of the unit cell 1. Then, the unit casing 1 covers the front casing 4 from the side of the light-emitting surface member 3, and is integrated with the unit casing 1, thereby completing the backlight unit of the present embodiment. Unit box! The space portion surrounded by the light reflecting surface member 2 and the light emitting surface member 3 becomes the hollow light guiding region 10. The light-reflecting surface member 2 is formed by laminating a material having high reflectivity and diffuse reflectivity, such as a white PET film or a white ink, on a substrate such as a metal or a resin, and is formed into a shape that changes in distance from the light-emitting surface 3. Therefore, the luminance distribution in the light-emitting surface member 3 can be made uniform. As the material having light diffusing reflectivity, in addition to the above, a light-transmitting diffusion material may be applied to a highly reflective aluminum having specular reflectivity. The light-emitting surface member 3 is formed by a minimum of light passing through the diffusing plate 3a, and more overlapping the upper diffusion sheets 3B, 3C, and the optical sheet such as the lens sheet 3D; and the mountain light is reflected by the hollow light guiding region 10' The light reflected by the member 2 is uniformly diffused and emitted, thereby achieving an operation of improving the brightness of the light-emitting surface without unevenness. The unit case 1 is formed of a highly thermally conductive metal such as aluminum alloy. The LED substrate 5 is disposed in each of the side faces of the cell case 1 which are parallel to the ridgeline of the light reflecting surface member 2. The LED substrate 5 is formed on an elongated wiring substrate 6 having a width that can be accommodated on the side surface of the unit case 1, and a plurality of LEDs 71 are adhered to each other in a row or a plurality of columns. The wiring board 6 is made of a metal such as a high thermal conductivity aluminum or a copper alloy, or a ceramic such as aluminum nitride, and is fixed to the side wall of the cell thermal insulation -8-200817777 by the screw, the adhesive, or the like. . Further, between the wiring board 6 and the side wall of the unit case 1, a double-sided tape, a sheet, a grease or the like having high thermal conductivity is preferably interposed. The LEDs 7 mounted on the LED substrate 5 are three-color LEDs of red, green, blue, etc., which are arranged in order to synthesize the desired ratio of white chromaticity; or by blue LED chips and yellow phosphors. The combination is to emit a plurality of white LEDs. Then, between the emitting side of the LED substrate 5 and the hollow light guiding region 10, an elongated LED collimator 9 is disposed, which covers the arrangement of the LEDs 7, and is formed with a concave light radiated by the LED 7 into the light. The incident surface formed by the groove 8. The LED collimator 9 is a groove 8 that receives the radiation emitted by the LEDs 7 mounted on the LED substrate 5 into the light, and a total reflection surface that is bent by connecting the upper and lower ends of the groove 8, and The contact is formed by combining the radiating surface of the plurality of curved faces; and is an optical member for condensing light of the radiating surface to be slightly parallel light to the hollow light guiding region 10; for example, acrylic acid Or a transparent resin such as polycarbonate or glass. As shown in detail in Figs. 3 and 4, the LED collimator 9 is formed with a groove 8 on the side of the incident portion facing the column of the LEDs 7. The groove wall surface of the groove 8 is a convex-shaped incident surface InA that guides the radiation light at an angle close to the optical axis of the LED 7 into the body; and a plane-shaped incident surface Ιη that emits the radiation light at an angle away from the optical axis of the LED 7 into the body. , ΙπΒ2. The LED collimator 9 is located on the lower side and the upper side in the figure, and is curved to be a total reflection surface TIR1, TIR2 capable of totally reflecting light in the body. The exit portion 200817777 of the LED collimator 9 is a convex-shaped exit surface ExA corresponding to incident light from the incident surface InA; and is totally reflected by the total reflection surface ΤIR 1 and ΤIR 2 after being incident from the incident surfaces ΙηΒΙ and ΙπΒ2. The concave curved surface shape of the light ray is X Β 1, ΕχΒ2. In the backlight unit of the above-described embodiment, as shown in detail in FIG. 4, the LED collimator 9 can condense the light from the LED 7 in the LED substrate 5 to the thickness direction of the hollow light guiding region 1 and into the thickness direction. The hollow light guiding area 10 is here. That is, in the LED collimator 9, the light RYA incident from the LED 7 to the incident surface InA is refracted by the incident surface InA and the exit surface ExA of the convex shape, and is concentrated in the thickness of the hollow light guiding region 1A. direction. Further, the light rays RYB1 and RYB2 incident on the incident surfaces ΙηΒ1, ΙηΒ2 are condensed in the thickness direction of the hollow light guiding region 10 by the total reflection of the total reflection surfaces TIR1 and TIR2 and the refraction of the emission surfaces ExB1 and ExB2. . The light rays RYA, RYB1, and RYB2 emitted from the LED collimator 9 to the hollow light guiding region 1 are reflected in the direction of the light-emitting surface member 3 by the reflecting surface of the reflecting surface member 2 whose shape is optimized. The light-emitting surface of the light-emitting surface member 3 is emitted in a state of high brightness and no unevenness in brightness. According to the backlight unit of the present embodiment, by the presence of the LED collimator 9, the light emitted from the light source, that is, the LED 7 at a wide angle, can be concentrated by the high efficiency and narrow angle of the light utilization efficiency of 80% or more. Light, the reflection loss in the hollow light guiding region 1 控制 is controlled to a minimum, and the brightness can be further improved than the backlight unit of the previous hollow mode. Moreover, the backlight unit of the previous hollow mode, in order to enable the light to reach the far distance from the light source, is to reflect the reflective surface of the hollow light guiding region as a specular reflection, or near the mirror surface of the -10-200817777 reflection characteristic, while emitting light In the case of the backlight unit of the present embodiment, since the light collecting property of the light source is high, even if the reflecting surface is diffusely reflective, brightness uniformity can be improved, and locality can be prevented. The production of the squall line. 5 is a pair of LED light sources 5 respectively disposed on opposite sides of the light-emitting surface for the backlight unit 30 of the present embodiment, which is caused by a right-angle direction of the light source lines (orthogonal to the LED array direction or The direction parallel to the optical axis direction of the LED is taken as the luminance distribution measurement line 3 1, and the luminance distribution between the light source lines caused by the pair of LED light sources 5 on the luminance distribution measurement line 3 1 is shown. Further, in this case, the LED light source 5 is disposed in the backlight unit 30 of Fig. 5(a) so as to be opposed to the upper and lower sides. (Second Embodiment) A backlight unit according to a second embodiment of the present invention will be described with reference to Figs. 6 and 7 . The backlight unit of the present embodiment is characterized in that it is an LED collimator 9A, and is shown in FIGS. 6 and 7; and the LED collimation of the first embodiment shown in FIGS. 1 and 2 is used. The device 9 has the same shape, but the incident surfaces InA, InB1, and InB2 formed by the groove wall surface of the groove 8A are used as the kneading surface. Further, in the present embodiment, the other structure is common to the backlight unit of the first embodiment shown in Figs. 1 and 2 . In the backlight unit of the present embodiment, as shown in Fig. 7, the light from the LEDs 7 on the LED substrate 5 enters the LED collimator 9 on the incident surfaces InA, InB1, and InB2 formed on the groove wall surface of the groove 8A. At the same time, it will efficiently spread toward the LED collimator. Thereby, the light from the LEDs 7-11 to 200817777 is diffused into the entire body of the LED collimator 9, and is emitted from the exit faces ExA, ExB1, and ExB2 to the hollow light guiding region 10. Then, as in the first embodiment, the light emitted from the LED collimator 9A to the hollow light guiding region 1 is reflected in the direction of the light emitting surface member 3 on the reflecting surface of the reflecting surface member 2 whose shape is optimized. On the other hand, the light-emitting surface of the light-emitting surface member 3 is emitted in a state of high brightness and no unevenness in brightness. In addition, in the present embodiment, the entrance faces ΙηΑ, ΙηΒΙ, and Ιιι2 of the LED collimator 9A formed by the groove wall surface of the groove 8A are all prism faces, but only one or both of them may be used as the face. Improve light diffusion. (Third Embodiment) A backlight unit according to a third embodiment of the present invention will be described with reference to Figs. 8 and 9 . The backlight unit of the present embodiment is characterized in that it is an LED collimator 9B, and is shown in Figs. 8 and 9; and the LED collimation of the first embodiment shown in Figs. 1 and 2 is used. The device 9 has the same shape, but the both ends of the longitudinal direction are interrupted by the groove 8B, and the groove end wall surface of the groove 8B is used as the end entrance surface inC; and the end face of the LED collimator 9B is made. It is the end total reflection surface TiR3. Further, in the present embodiment, the other structure is also common to the backlight unit of the first embodiment shown in Figs. 1 and 2 . In the backlight unit of the present embodiment, as shown in Fig. 9, the light from the LEDs 7 on the LED substrate 5 enters the LED collimator 9 from the entrance faces Ιη, Ιη, and InB2 formed by the groove walls of the grooves 8B. At the same time, both end portions in the longitudinal direction are also incident from the end incident surface InC. Then, inside the LED collimator 9B, as shown in Fig. 4, the incident light is refracted or totally -12-200817777 reflected, effectively condensed from the exit surfaces ExA, ExB 1, ΕχΒ 2 and emitted to the hollow light guiding region 10; At the same time, at both ends of the LED collimator 9Β, as shown in FIG. 9, the light that is incident from the end incident surface InC into the end body is totally reflected by the end total reflection surface TIR3, from the exit surface. ExA, ExB 1, and ExB2 are emitted to the hollow light guiding region 10. As a result, in the backlight unit of the present embodiment, the light from the LEDs 7 at the end portions of the LED substrate 5 can suppress the reflection and absorption loss when contacting the wall surface of the unit cell 1, and the brightness of the light-emitting surface can be improved. Further, in the third embodiment, as in the second embodiment, the groove wall surface or the plurality of faces of the groove 8B may be formed as a kneading surface, whereby the diffusion of incident light to the LED collimator 8B can be improved. (Fourth Embodiment) A backlight unit according to a fourth embodiment of the present invention will be described with reference to Figs. 10 to 12 . The backlight unit of the present embodiment is characterized by a structure of the LED substrate 5, and a wavelength conversion sheet 130 of the inner surface side of the light-emitting surface member 3 disposed on the outer surface side of the hollow light guiding region 2. Further, in the present embodiment, the other structure is also common to the backlight unit of the first embodiment shown in Figs. 1 and 2 . As shown in FIGS. 10 and 11 , in the backlight unit of the present embodiment, the LED substrate 5 is arranged such that a blue LED 7B that emits blue light and a red LED 7R that emits red light are alternately arranged on the wiring substrate 6 . Unlike other implementations, there are usage color LEDs. Further, in order to mix blue light and red light and green light as white light, the inner surface side of the light-emitting surface area 1 is the outer surface side, and the inner surface side of the light-emitting surface member 3 is provided with blue. The color light is converted into a wavelength conversion sheet of green light 1 130. -13- 200817777 The blue LED 7B and the red LED 7R are mounted on the wiring substrate 6 in a ratio of, for example, a ratio of 2:1 or a ratio of 2:1. These LEDs may be either surface-illuminated or end-illuminated. However, it is inlaid so that the light can be incident into the groove 8 of the collimator 9. The peak wavelength of the emitted light of the red LED 7R is preferably in the range of 5 90 to 670 nm. Such a light-emitting element can be realized by using, for example, an InGaA1P-based compound semiconductor. For the various purposes, the composition of the InGaAlP active layer of the red LED 7R can be adjusted to obtain the most desirable peak wavelength in this wavelength range. On the other hand, the peak wavelength of the emitted light of the blue LED 7B is preferably in the range of 420 to 48 Onm. Such a light-emitting element can be realized by using, for example, an InGaAIN-based compound semiconductor. The optimum peak-to-peak wavelength in this wavelength range can be obtained by adjusting the composition of the InGaAIN active layer of the blue LED 7B for various purposes. The wavelength conversion sheet 130 is formed of a resin. That is, the wavelength conversion sheet 130 is formed by dispersing a phosphor in a resin to form a sheet. This wavelength conversion sheet 130 is a person who applies a phosphor to the surface (or the back surface) of the light-transmitting film. The phosphor dispersed or contained in the wavelength conversion sheet 130 absorbs blue light emitted from the blue LED 7B and emits green light. The peak wavelength of green light is preferably in the range of 520 to 560 nm. Examples of such a fluorescent material include those in which Cu or A1 is added to ZnS, or Eu or η is added to (Ba·Mg)Α1〇017. 12th to 12th, the cross-sectional structure of the wavelength conversion sheet 130 is exemplified. In other words, Fig. 12A shows a wavelength conversion sheet 130 formed by coating a phosphor layer 130f on the surface of a film-like mother substrate 130c such as a resin. Further, Fig. 12B shows a wavelength conversion sheet 130 formed by dispersing a phosphor in a resin matrix. Fig. 12C shows a layer-converted light-transmissive film 130c in which a layer 130s coated or dispersed with a phosphor is provided, and a wavelength conversion sheet 130 of this configuration is provided. Further, the wavelength conversion sheet 130 does not need to have an integral structure, and the plurality of thin films 130s containing the phosphor may be laminated as shown in Fig. 2D. Further, the wavelength conversion sheet 130 may be separated from the light-emitting surface member 3 or may be integrally formed. According to the present embodiment, the wavelength of the green light can be adjusted by adjusting the material or composition of the phosphor included in the wavelength conversion sheet 130. For example, when used as a backlight of an LCD, light rays conforming to the transmission characteristics of the green color filter of the LCD can be obtained by appropriately selecting the material or composition of the phosphor contained in the wavelength conversion sheet 130. As a result, there is no need to use less efficient green LEDs. As a result, the overall cost can be reduced and higher brightness and color reproducibility can be obtained. Further, according to the present embodiment, the green light emission is obtained not from the LED substrate 5 side but by the wavelength conversion sheet 130 from the light emitting surface side. Thereby, the inconsistency in characteristics caused by the individual differences of the green LEDs generated when the green LEDs are used can be eliminated. Further, since the wavelength conversion sheet 130 is excited by the blue light emission in which the light reflecting surface member 2 is improved in uniformity, it is not necessary to perform wavelength conversion for uniform green luminance distribution of the light emitting surface of the light emitting surface member 3. Each portion of the sheet 130 is adjusted for the concentration distribution of the phosphor for wavelength conversion. That is, the brightness of the wavelength conversion phosphor is adjusted so that the entire wavelength conversion sheet is the same as the brightness of the blue wavelength conversion light, which is 5 times or more of the blue excitation light -15-200817777 degree. can. In this way, finally, the light emitted from the light-emitting surface member 3 can obtain white light corresponding to the human visual perception. Further, according to the present embodiment, the brightness of the red light can be controlled to about 1/5 of the green light by independently controlling the current 施加 applied to the red LED 7R. Similarly, the brightness ratio of blue light to red light can also be controlled, so the color temperature can also be adjusted within a certain range. At this time, the control circuit is simpler than adjusting the three-color LEDs in the so-called RGB arrangement by RGB three-color LEDs. When the red LED, the blue LED, and the phosphor that emits green light by absorbing blue light are sealed in the same package and become a white LED package that emits white light, the green luminance/blue luminance ratio is mixed once the phosphor is mixed. It will be fixed and cannot be adjusted afterwards. It is actually very difficult to mix the phosphors into each package at a specific distribution and concentration. That is, the ratio of green brightness/blue brightness is often different in each package. Therefore, after the completion of the manufacturing, it is difficult to control to a specific brightness ratio (5:1) using a packaged product without post-engineering, which will delay the yield and need to be selected. In contrast, according to the present embodiment, the blue L E D 7 B and the long conversion sheet 1 30 including the phosphor are respectively configured. Thus, by appropriately combining these, the brightness balance of the blue light and the green light can be easily adjusted. For example, a plurality of wavelength conversion sheets 130 having different green phosphor contents are prepared in advance, and the brightness of the blue light emitted from the outer surface side of the surface light-emitting member 3 is selected, and any one of the plurality of wavelength conversion sheets 130 is selected to be blue. The balance of shade and green 16-200817777 light is adjusted to the best. Further, for example, as the wavelength conversion sheet 103, as shown in Fig. 2D, when the laminated structure of the plurality of thin films containing the phosphor is laminated, the effect of easily changing the phosphor content can be obtained. That is, the optimum balance can be obtained by merging the necessary number of sheets in accordance with the blue light luminance emitted from the blue phosphor LED 7B and the green/blue balance required for the respective applications. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded perspective view of a backlight unit according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view showing the backlight unit of the first embodiment. Fig. 3 is a partially cutaway perspective view of the LED collimator used in the first embodiment. Fig. 4 is a cross-sectional view showing the condensing characteristics of the LED collimator in the first embodiment. Fig. 5 is a graph showing the luminance distribution characteristics of the backlight unit of the first embodiment. Fig. 6 is a partially cutaway perspective view showing the LED collimator used in the backlight unit of the second embodiment of the present invention. Fig. 7 is a cross-sectional view showing the light diffusion characteristics of the LED collimator in the second embodiment. Fig. 8 is a partially cutaway perspective view showing an LED collimator used in the backlight unit of the third embodiment of the present invention. -17- 200817777 Fig. 9 is a cross-sectional view showing the operation of light rays on the fine surface of the LED in the third embodiment. Fig. 10 is an exploded perspective view showing a backlight unit according to a fourth embodiment of the present invention. Fig. 1 is a cross-sectional view of a backlight unit according to a fourth embodiment of the present invention. Fig. 12A is a cross-sectional view showing a configuration example of a wavelength conversion sheet according to the fourth embodiment. Fig. 12B is a cross-sectional view showing another structural example of the wavelength conversion sheet in the fourth embodiment. Fig. 12C is a cross-sectional view showing still another structural example of the wavelength conversion sheet in the fourth embodiment. The Fig. 12D is a cross-sectional view showing still another structural example of the wavelength conversion sheet in the fourth embodiment. [Description of main component symbols] 1 : Cell box 2 : Light reflecting surface member 3 : Light emitting surface member 3 A : Light transmitting diffusing plate 3B : Diffusion sheet 3C : Diffusion sheet 3 D : Lens sheet 4 : Front frame -18 - 200817777 5 : LED substrate 6 : wiring substrate
7 ： LED7 : LED
7R ··紅色 LED 7B :藍色LED 8 :凹溝 8A :凹溝 8B :凹溝 9 : LED準直器 9A : LED準直器 9B : LED準直器 1 〇 :中空導光區域 3 0 :背光單元 3 1 :亮度分布測定線 1 3 0 :波長轉換薄片 130c :透光性薄膜 130f :螢光體層 1 3 0 s :層、薄膜 InA :入射面 InBl :入射面 InB2 :入射面 InC :端部入射面 ExA :出射面 ExB 1 :出射面 -19- 2008177777R ··Red LED 7B : Blue LED 8 : Groove 8A : Groove 8B : Groove 9 : LED Collimator 9A : LED Collimator 9B : LED Collimator 1 〇 : Hollow Light Guide Area 3 0 : Backlight unit 3 1 : luminance distribution measurement line 1 3 0 : wavelength conversion sheet 130c : light transmissive film 130 f : phosphor layer 1 3 s : layer, film InA: incident surface InB1 : incident surface InB2 : incident surface InC : end Part incident surface ExA: exit surface ExB 1 : exit surface -19- 200817777
ExB2 :出射面 RYA :光 RYB1:光 RYB2 ··光 TIR1 :全反射面 TIR2 :全反射面ExB2: exit surface RYA: light RYB1: light RYB2 ··light TIR1: total reflection surface TIR2: total reflection surface